已知:x+y=2,求(x2-y2)2-8(x2+y2)的值.
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知2x+y=7,x2+y2=5,求(4x+2y)2-3x2-y2+2(1-y2)的值.
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值
已知实数x、y满足(x2+y2)(x2+y2-1)=2,则x2+y2的值为______.
已知(x+y)2=18,(x-y)2=6,分别求x2+y2及x2+3xy+y2的值.
已知x2+y2-10x-6y+34=0,求(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy 的值.
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值.